Sensor assembly for detecting position of spring-loaded target surface and method of detecting position through multiple structures

ABSTRACT

A sensor assembly includes a first structure and a second structure disposed radially outwardly of the first structure. Also included is a sensor body extending through the first and second structures, the sensor body having first and second ends, the first end disposed proximate a first environment defined by the first structure and the second end located radially outwardly of the second structure. Further included is a first sealing assembly configured to operatively couple the sensor body to the second structure and to accommodate movement of the sensor body. Yet further included is a position sensor operatively coupled to the sensor body, the position sensor configured to determine a position of a target located within the first interior volume. Also included is at least one biasing member in contact with the target to bias the target into constant operative contact with the sensor body.

FEDERAL RESEARCH STATEMENT

The invention disclosed herein was made with Government support underContract No. N00014-09-D-0821 with the United States Navy. TheGovernment may have certain rights in the subject matter disclosedherein.

BACKGROUND OF THE INVENTION

The embodiments herein generally relate to sensor assemblies and, moreparticularly, to a sensor assembly extending through a plurality ofstructures which separate distinct operating environments, as well as amethod of detecting position of a target through multiple structures.

Adjustable guide vanes within compressor sections of a turbine engineare known and are able to be monitored with sensing equipment. Sensingequipment in a turbine section of a gas turbine engine poses morechallenges due to a high temperature and pressure environment therein.Typically, a hot gas path of a turbine section is surrounded by multiplelayers of structures that are subjected to distinct thermal growthcycles due to the distinct environments defined by each structure.Challenges with sensing include operating in extreme hot pressurizedenvironments and bringing the signal out to the outer surface of theengine through multiple engine sections. The distinct thermal growthrates noted above are combined with tolerance stacking of the varioushardware pieces.

BRIEF DESCRIPTION OF THE INVENTION

According to one embodiment, a sensor assembly includes a firststructure defining a first interior volume having a first environmentwith a first temperature and a first pressure. Also included is a secondstructure disposed radially outwardly of the first structure anddefining a second interior volume having a second environment with asecond temperature and a second pressure each lower than the firsttemperature and the first pressure. Further included is a sensor bodyextending through the first structure and the second structure, thesensor body having a first end and a second end, the first end disposedproximate the first environment and the second end located radiallyoutwardly of the second structure. Yet further included is a firstsealing assembly configured to operatively couple the sensor body to thesecond structure and to accommodate movement of the sensor body due torelative movement between the first structure and the second structure.Also included is a position sensor operatively coupled to the sensorbody, the position sensor configured to determine a position of a targetlocated within the first interior volume. Further included is at leastone biasing member in contact with the target to bias the target intoconstant operative contact with the sensor body.

According to another embodiment, a method of detecting an angularposition of a target through multiple structures separating multipledistinct environments. The method includes penetrating a plurality ofstructures with a sensor body, a first end of the sensor body beingdisposed within a first interior volume having a first environment witha first temperature and a first pressure, a second end of the sensorbody being disposed in environment having a temperature and a pressureeach lower than the first temperature and the first pressure, the secondend having a sensor mounted thereto. The method also includes disposingsensor instrumentation of a position sensor into close proximity of acontoured surface of the target disposed within the first interiorvolume, the contoured surface comprising an inclined plane that variesas a function of rotational position of the target. The method furtherincludes biasing the contoured surface into constant contact with thefirst end of the sensor body.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter which is regarded as the invention is particularlypointed out and distinctly claimed in the claims at the conclusion ofthe specification. The foregoing and other features and advantages ofthe invention are apparent from the following detailed description takenin conjunction with the accompanying drawings in which:

FIG. 1 is a perspective view of a portion of a turbine section having aplurality of structures separating a plurality of volumes havingdistinct operating environments; and

FIG. 2 is a partial cross-sectional view of a sensor assembly extendingthrough the plurality of structures of the turbine section for detectionof a spring-loaded target.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1, a portion of a turbine section is illustrated andgenerally referenced with numeral 10. In an exemplary embodiment, theturbine section 10 is part of an aircraft engine, such as a highpressure turbine or a low pressure turbine. Illustrated is a portion ofa single stage of the turbine section 10. Included is a plurality ofadjustable vanes 12, such as adjustable stator vanes and which may bereferred to herein interchangeably, that are configured to rotate in acontrollable manner. The number of vanes within a single stage may varydepending upon the application. In one embodiment, the number ofadjustable vanes varies from about 20 vanes to about 40 vanes. Rotationof the adjustable vanes 12 is desirable due to increased efficiency andperformance of the aircraft engine. Specifically, the adjustable vanes12 may be rotated to optimal angles corresponding to different operatingconditions of the aircraft engine. For example, improvements in specificfuel consumption are seen by adjusting the vanes based on certainoperating conditions. Segments of the guide vanes 12 are typicallyrotated concurrently by a linkage mechanism or the like that includes acrank arm or other mechanical structure operatively coupled to the guidevanes 12. It is to be appreciated that all or only some of the totalnumber of vanes within a stage may be rotatable. For example, in someembodiments, only half of the total vanes are rotatable. In such anembodiment, every other vane may be rotated. As one can understand, anyfraction of the total number of vanes may be rotated and the spacingbetween the vanes that are adjustable may vary. Numerous contemplatedcombinations may be suitable for different embodiments.

The adjustable vanes 12 are disposed within a first interior volume 14having a harsh operating environment (also referred to herein as a firstenvironment) where a hot gas passes over them in an effort to convertthe thermal energy of the hot gas to mechanical work for propulsion ofthe aircraft. The first interior volume 14 is defined by a firststructure 16, such as a turbine casing, and the first environment has afirst temperature and a first pressure. The precise temperature andpressure will vary depending upon the type of aircraft engine and theoperating conditions, but reference to the first temperature and thefirst pressure will be appreciated based on their values relative toother environments of other volumes discussed herein. Disposed radiallyoutwardly of the first structure 16 is a second structure 18, such as aninner casing. An inner surface of the second structure 18 and an outersurface of the first structure 16 define a second interior volume 20.The second interior volume 20 has a second environment therein, with thesecond environment having a second temperature and a second pressure.The precise temperature and pressure of the second environment will varydepending upon the type of aircraft engine and the operating conditions,but irrespective of those variables, the second temperature and thesecond pressure are lower than the first temperature and the firstpressure, respectively. Disposed radially outwardly of the secondstructure 18 is a third structure 22, such as an outer casing. An innersurface of the third structure 22 and an outer surface of the secondstructure 18 define a third interior volume 24. The third interiorvolume 24 has a third environment therein, with the third environmenthaving a third temperature and a third pressure. The precise temperatureand pressure of the third environment will vary depending upon the typeof aircraft engine and the operating conditions, but irrespective ofthose variables, the third temperature and the third pressure are lowerthan the second temperature and the second pressure, respectively. Anambient environment 23 is located radially outwardly of the thirdstructure 22. The ambient environment 23 has an ambient temperature andan ambient pressure that are lower than the third temperature and thethird pressure, respectively. It is to be understood that more or lessstructures, and therefore volumes with different environments, may bepresent. The embodiments described herein benefit multi-layer structureswith different environments, as will be appreciated from the descriptionbelow.

Although the structures, volumes and environments described above andillustrated are in the context of an aircraft engine, it is to beappreciated that any structure requiring separation of multiple volumesthat are subjected to distinct environments will benefit from theembodiments described herein.

Referring now to FIG. 2, with continued reference to FIG. 1, a sensorassembly 30 configured to penetrate multiple structures is illustratedin detail. The sensor assembly 30 may be used in conjunction with anystructure or assembly that has a plurality (i.e., two or more) ofstructures that define multiple distinct environments. The sensorassembly 30 is operatively coupled to each of the plurality ofstructures and includes features that accommodate relative movementbetween the plurality of structures that occurs due to the distinctoperating environments.

In the illustrated exemplary embodiment of FIG. 1, the sensor assembly30 penetrates structures of the turbine section 10 and is subjected tothe distinct environments that are defined by those structures. Inparticular, the sensor assembly 30 includes a sensor body 32 thatpenetrates through apertures of at least two structures, such as a firstaperture of the first structure 16, a second aperture of the secondstructure 18 and a third aperture of the third structure 22. It is to beappreciated that the sensor body 32 may penetrate only two structuresand may penetrate more than the three illustrated structures as well,depending upon the particular structure or assembly that the sensorassembly 30 is employed with. The sensor body 32 extends from a firstend 34 to a second end 36. The first end 34 is disposed radiallyinwardly proximate the first structure 16 and is operatively coupledthereto. Coupling of the first end 34 of the sensor body 32 to the firststructure 16 may be facilitated in any known securing process, such aswelding, mechanical fasteners or threaded connection. The first end 34may protrude slightly into the first interior volume 14, such that it isexposed to the first environment.

In one embodiment, a sensor 42 is located proximate the second end 36and a signal is routed thru an interior cavity 38 of the sensor body 32that is defined by an interior wall 40 of the sensor body 32. Theinterior cavity 38 may be formed of any suitable geometry, such ascylindrical, for example. The interior cavity 38 provides a protectedpath for the sensor signal to be routed from the first end 34, wheresensing detection is made, to the second end 36 of the sensor body 32,where the sensor 42 is operatively coupled. The sensor 42 may be coupledto the sensor body 32 proximate the second end 36 in any suitablemanner. The second end 36 is disposed outside of the first interiorvolume 14. In the exemplary embodiment, the second end 36 of the sensorbody 32, and therefore the sensor 42, is located in the ambientenvironment 23 radially outwardly of the third structure 22, butplacement of the sensor 42 in one of the more benign environments (e.g.,second interior volume 20 or third interior volume 24) is contemplated.Placing the sensor 42 in a location outside of the harsh environment ofthe first interior volume 14, and possibly outside of the second andthird interior volumes 20, 24, allows for a wider selection of sensors.Wider selection is available based on certain sensors having sensitivelimitations on the operating environments in which they may be disposed.

The sensor 42 is connected to the sensor instrumentation (not shown)that is housed within a less harsh environment. The sensor 42 and sensorinstrumentation is configured to detect at least one characteristic of atarget 13, such as the adjustable stator vanes 12 disposed within thefirst interior volume 14. The terms target and adjustable stator vanes12 may be used interchangeably herein as the target and the vane may bea, single integrally formed structure or may be distinct components thatare operatively coupled to each other in a fixed manner, such thatrotation of the vane imparts corresponding rotation of the target. “Atleast one characteristic” refers to any characteristic that is commonlymeasured by sensors. For example, position of the target, temperature ofthe target and pressure proximate the target are all examples ofcharacteristics that may be detected by the sensor 42. In an exemplaryembodiment, the sensor 42 is configured to detect an angular position ofthe adjustable stator vane 12 via signals generated from the target 13located proximate the first end 34 of the sensor body 32 and that isoperatively coupled to the adjustable stator vane 12. The interactionbetween the sensor instrumentation and the target 13 will be describedin detail below.

In another embodiment, a sensor 100 (shown schematically in phantom inFIG. 2) may be located proximate the first end 34 of the sensor body 32in a coupled manner. Some sensors are able to withstand more stressfuloperating environments and may be suitable for use in such a location.The sensor 100 includes a sensor face 102 that is located in closeproximity to the target 13 and the interaction between the sensor face102 and the target 13 will be described in detail below.

Remotely locating the sensor 42 in a less harsh environment, such as theambient environment 23, ensures accurate and reliable operation of thesensor 42, thereby providing more accurate measurements, but asdescribed above it is contemplated that a suitable sensor 100 is locatedproximate the harsh environment. Either way, relative movement of theplurality of structures that the sensor assembly 30 penetrates and isoperatively coupled to leads to potential detrimental effects related toaccuracy and reliability of the measurements. The relative movement isattributed to effects of the distinct operating environments, such asdifferent thermal growth rates of the structures. The relative movementof the structures, 16, 18, 22, may be in the radial, axial and/orcircumferential direction.

To accommodate the relative movement of the structures, one or moresealing assemblies are provided to operatively couple the sensor body 32to respective structure(s). The number of sealing assemblies will dependupon the number of structures to which the sensor body 32 is topenetrate and to be operatively coupled to. In the illustratedembodiment, operative coupling of the sensor body 32 to the firststructure 16 is made by a mechanical process, such as a threadedconnection, as described in detail above. The sensor body 32 isoperatively coupled to the second structure 18 with a first sealingassembly 50.

The first sealing assembly 50 includes a radial seal 52 that is disposedin a groove 54 of the sensor body 32. The groove 54 extendscircumferentially around an outer surface 56 of the sensor body 32 in aradial location proximate that is at the radial location of the secondstructure 18. The groove 54 extends completely around the sensor body32. The radial seal 52 is configured to be at least partially disposedwithin the groove 54 and is in abutment with a radial seal backer 58that is sandwiched between the radial seal 52 and a radial seal retainer60. The radial seal retainer 60 is disposed in a notch 62 of the sensorbody 32. As with the radial seal 52, the radial seal backer 58 and theradial seal retainer 60 each extend completely around the sensor body32. The abutment of the radial seal retainer 60 and the radial sealbacker 58, in combination with the abutment of the radial seal backer 58and the radial seal 52, biases the radial seal 52 to fix the radial seal52 in a radial direction. The radial seal retainer 60 is typically asubstantially rigid structure, such that stiff support of the radialseal 52 is achieved. The radial seal 52 is at least partially flexiblein order to accommodate relative movement of the structures in a radialdirection, thereby allowing the sensor body 32 to move slightly in theradial direction, while maintaining a sealed arrangement.

The first sealing assembly 50 also includes a slider plate 64. Theslider plate 64 is a single, integrally formed structure that includes acylindrical portion 68 and a ring portion 70. The cylindrical portion 68extends circumferentially around the sensor body 32 and, moreparticularly, around the radial seal 52. The cylindrical portion 68 isin abutment with the radial seal 52 to fix the radial seal 52 in axialand circumferential directions. The ring portion 70 is orientedsubstantially perpendicularly to the cylindrical portion 68 and isdisposed in contact with a radially inner surface of a mounting body 90that is coupled to the second structure 18. As shown in the illustratedembodiment, the mounting body 90 may be a ring-like structure thatdirectly mounts to the second structure 18 via mechanical fasteners 92,however, alternative geometries and coupling processes may be employed.The mounting body 90 may be a single ring that extends circumferentiallyaround the entire sensor body 32 or may be segmented. A slider plateretainer 72 is disposed within a recess 74 of the mounting body 90 andis in abutment with the slider plate 64 to fix the slider plate in aradial direction. The slider plate retainer 72 is typically asubstantially rigid structure, such that stiff support of the sliderplate 64 is achieved. The slider plate 64 is at least partially flexiblein order to accommodate relative movement of the structures in both thecircumferential and axial directions, thereby allowing the sensor body32 to move slightly in these directions, while maintaining a sealedarrangement.

As described in detail above, additional structures, such as the thirdstructure 22 may require penetration and operative coupling by thesensor assembly 30. In such embodiments, additional sealing assembliesidentical to that described above in conjunction with the first sealingassembly 50 are employed. For example, a second sealing assembly 80 isillustrated. The second sealing assembly 80 includes identical sealingcomponents to accommodate relative movement of the first, second andthird structures 16, 18, 22. Such components are illustrated and labeledwith corresponding numerals associated with the sealing components ofthe first sealing assembly 50. For purposes of description, additionalsealing structures are not described or illustrated, but it is to beappreciated that additional sealing assemblies may be included to coupleto additional structures.

As described above, the sensor 42 may be distanced from the harshenvironment of the first interior volume or may be the sensor 100described above that is located proximate such an environment.Regardless of the precise location of the sensor, 42 or 100, the sensorface 102 usually requires direct line of sight to the to the target 13.More particularly, the sensor face 102 is directed at the contouredsurface 104 of the target 13. While it is contemplated that thecontoured surface 104 may be in the form of any non-planar geometry, inan exemplary embodiment, the contoured surface 104 is an inclined planethat extends around at least a portion of the radially outer surface ofthe target 13.

The sensor 42, 100 is configured to process a specific signal based onthe distance between the target 12 (i.e., contoured surface 104) and thesensor 42, 100. As the target 13 is rotated, the distance detected bythe sensor 42, 100 will vary due to the contoured (e.g., inclined)surface 104. Based on this feature, the precise distances detectedcorrespond to distinct angular positions of the target 13, as thesurface and hence distance varies with rotational displacement of thetarget 13. The target 13 has a surface, including the contoured surface104, that has an area larger than an area of the sensor face 102,thereby facilitating contact between the sensor body 32 and the target13 during a full range of rotation of the target 13. The distancebetween the target 13 and the sensor 42, 100 remains constant due to thespring 106. It is contemplated that the sensor face 102 is alwaysconstantly spaced from the contoured surface 104 of the target 13 or aninitial contact point may be made at one location of the contouredsurface 104.

To maintain an accurate detection of the distance between the contouredsurface 104 and sensor face 102, it is desirable to maintain a referenceinterface between the components. Erroneous distance measurements may becaused by relative movement of the target 13 and the sensing equipmentdue to thermal changes during a range of operating conditions and/or bytolerance stack of the various components. To establish a constantreference interface, the embodiments described herein require the target13 to be in constant contact with the sensor body 32 or sensor 42,100.This is achieved with at least one biasing member 106 disposed incontact with the target 13 to bias the target 13 radially outward intocontact with the first end 34 of the sensor body 32. In an exemplaryembodiment, the biasing member 106 is a spring, but it is to beappreciated that any component or assembly capable of biasing the target13 into contact with the sensor body 32 may be employed. There may be asingle biasing member present or a plurality of biasing members.Regardless of the precise configuration of the biasing member 106, asthermal variation occurs throughout the operating range, the biasingmember 106 keeps the target 12 loaded against the sensor body 32.

Advantageously, the embodiments described herein allow for penetrationthrough multiple temperature and pressure environments in order tomonitor signals deep within a harsh operating environment, such as a hotgas path of a turbine engine. Furthermore, the embodiments achieveaccurate positional sensing and detection of a target, such as theadjustable stator vane described herein. Other benefits include theprovision of greater selection of the sensing technology that is bestsuited to meet performance requirements.

While the invention has been described in detail in connection with onlya limited number of embodiments, it should be readily understood thatthe invention is not limited to such disclosed embodiments. Rather, theinvention can be modified to incorporate any number of variations,alterations, substitutions or equivalent arrangements not heretoforedescribed, but which are commensurate with the spirit and scope of theinvention. Additionally, while various embodiments of the invention havebeen described, it is to be understood that aspects of the invention mayinclude only some of the described embodiments. Accordingly, theinvention is not to be seen as limited by the foregoing description, butis only limited by the scope of the appended claims.

What is claimed is:
 1. A sensor assembly comprising: a first structuredefining a first interior volume having a first environment with a firsttemperature and a first pressure; a second structure disposed radiallyoutwardly of the first structure and defining a second interior volumehaving a second environment with a second temperature and a secondpressure each lower than the first temperature and the first pressure; asensor body extending through the first structure and the secondstructure, the sensor body having a first end and a second end, thefirst end disposed proximate the first environment and the second endlocated radially outwardly of the second structure; a first sealingassembly configured to operatively couple the sensor body to the secondstructure and to accommodate movement of the sensor body due to relativemovement between the first structure and the second structure; aposition sensor operatively coupled to the sensor body, the positionsensor configured to determine a position of a target located within thefirst interior volume; and at least one biasing member in contact withthe target to bias the target into constant operative contact with thesensor body.
 2. The sensor assembly of claim 1, wherein the positionsensor is coupled to the sensor body proximate the second end of thesensor body.
 3. The sensor assembly of claim 2, further comprisingsensor instrumentation extending through an interior cavity of thesensor body, wherein an end of the sensor instrumentation is locatedproximate the first end of the sensor body and in close proximity to thetarget.
 4. The sensor assembly of claim 3, wherein the target comprisesa contoured surface detected by the sensor instrumentation, wherein asignal obtained by the sensor instrumentation is based on a distancebetween the sensor instrumentation and the contoured surface of thetarget.
 5. The sensor assembly of claim 4, wherein the contoured surfacecomprises an inclined surface that varies with rotational displacementof the target.
 6. The sensor assembly of claim 4, wherein the end of thesensor instrumentation is constantly spaced from the contoured surfaceof the target.
 7. The sensor assembly of claim 4, wherein the end of thesensor instrumentation is in contact with the contoured surface at onelocation of the contoured surface.
 8. The sensor assembly of claim 4,wherein the contoured surface of the target comprises a larger area thanan area of the sensor instrumentation.
 9. The sensor assembly of claim1, wherein the position sensor is coupled to the sensor body proximatethe first end of the sensor body.
 10. The sensor assembly of claim 9,wherein the position sensor includes a sensor face located in closeproximity to the target.
 11. The sensor assembly of claim 9, wherein thetarget comprises a contoured surface detected by the sensor face,wherein a signal obtained by the position sensor is based on a distancebetween the sensor face and the contoured surface of the target.
 12. Thesensor assembly of claim 1, wherein the sensor assembly is disposed in aturbine section of an aircraft engine, the target is operatively coupledto an adjustable vane of the turbine section, and the first structurecomprises a turbine casing, the second structure comprises an innercasing and the third structure comprises an outer casing.
 13. The sensorassembly of claim 1, wherein the biasing member is at least one spring.14. A method of detecting an angular position of a target throughmultiple structures separating multiple distinct environments, themethod comprising: penetrating a plurality of structures with a sensorbody, a first end of the sensor body being disposed within a firstinterior volume having a first environment with a first temperature anda first pressure, a second end of the sensor body being disposed inenvironment having a temperature and a pressure each lower than thefirst temperature and the first pressure, the second end having a sensormounted thereto; disposing sensor instrumentation of a position sensorinto close proximity of a contoured surface of the target disposedwithin the first interior volume, the contoured surface comprising aninclined plane that varies as a function of rotational position of thetarget; and biasing the contoured surface into constant contact with thefirst end of the sensor body.
 15. The method of claim 14, furthercomprising detecting an angular position of the target based on adistance between the sensor instrumentation and the contoured surface.